smart url loading with a fallback strategy, fixes #4

main.js

@@ -96,30 +96,41 @@ async function createWindow() {
     });
 
     // show black window
-    // win.setKiosk(true);
+    win.setKiosk(true);
     win.show();
 
 
-    // load actual page from config file
+    // Load page from config file
     if (config != undefined && 'url' in config) {
         testAndLoadUrl(config.url);
+    } else {
+        try {
+            // Load file from data folder if available
+            fs.accessSync('/assets/data/index.html');
+            win.loadFile('/assets/data/index.html');
+        } catch {
+            // Load fallback page
+            win.loadFile('index.html');
+        }
     }
 
-    // load fallback page
-    // win.loadFile('index.html');
 }
 
 /**
  * Validates the url of a navigatio event against the list of allowed domains in
  * the config file. See https://www.electronjs.org/docs/latest/api/web-contents#event-will-frame-navigate
  * @param {Event} event 
+ * @returns `true` if the url is allowed, `false` otherwise
  */
+
 function validateDomain(event) {
-    console.log(event.type);
-    if (config == undefined) return;
+    if (config == undefined) return true;
 
     let url = new URL(event.url);
 
+    // allow local urls
+    if (['file:', 'file'].includes(url.protocol)) return true;
+
     if ('allowedDomains' in config && !config.allowedDomains.includes(url.hostname)) {
         event.preventDefault();
         log.info("Navigation to " + event.url + " prevented");
@@ -137,11 +148,11 @@ function validateDomain(event) {
 function testAndLoadUrl(testurl) {
     try {
         let url = new URL(testurl);
-
-        // It’s an online url, test if it’s reachable
+        // If it’s an online url, test whether it’s reachable
+        let delay = 1;
         if (['https:', 'http:', 'https', 'http'].includes(url.protocol)) {
             (async function () {
-                for await (const startTime of setInterval(1000)) {
+                for await (const startTime of setInterval(delay)) {
                     let reachable = linkExists(url.hostname);
                     if (reachable) {
                         log.info("Successfull access to " + url.hostname)
@@ -150,7 +161,8 @@ function testAndLoadUrl(testurl) {
                         // break the interval
                         break;
                     } else {
-                        log.warn("Could not reach " + url.hostname)
+                        log.warn("Could not reach " + url.hostname);
+                        delay = 1000;
                     }
                 }
             })();